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  • 2010-2014
  • 1985-1989  (262)
  • 1970-1974
  • 1965-1969  (132)
  • 1988  (262)
  • 1969  (132)
  • Atomic, Molecular and Optical Physics  (326)
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  • 2010-2014
  • 1985-1989  (262)
  • 1970-1974
  • 1965-1969  (132)
Year
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  • 1
    Electronic Resource
    Electronic Resource
    The minimum alveolar concentration of sevoflurane in cats (1988)
    Springer
    Journal of anesthesia 2 (1988), S. 113-114 
    Details
    ISSN: 1438-8359
    Keywords: Sevoflurane ; Minimum alveolar concentration ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Eight adult cats of either sex were studied. The minimal alveolar concentration (MAC) for sevoflurane in the cats was found to be 2.58 ± 0.30% (mean ± SD). The ratios of MAC values between sevoflurane and halothane, enflurane and isoflurane in cats were very similar to those ratios found in humans and dogs. This observation suggests that the results of this study are correct and allows us to estimate unknown MAC values for sevoflurane in other species using known MAC values for other anesthetic agents. (Doi M, Yunoki H, Ikeda K: The minimum alveolar concentration of sevoflurane in cats. J Anesth 2: 113–114, 1988)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s0054080020113
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  • 2
    Electronic Resource
    Electronic Resource
    Experimental hydrocephalus and hydrosyringomyelia. Computertomographic studies (1988)
    Springer
    Neurosurgical review 11 (1988), S. 87-94 
    Details
    ISSN: 1437-2320
    Keywords: Cat ; CSF ; CT scans ; experimental hydrocephalus ; syringomyelia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two methods were used to induce a model of experimental hydrocephalus and hydrosyringomyelia in the cat: a) injection of kaolin into the cisterna magna and b) closure of the lateral apertures of the fourth ventricle with cotton swabs. The pathological changes in the brain ventricles and the central canal of the spinal cord were monitored and documented at regular intervals by computed tomography (CT). The CT method is particularly advantageous for studies of this kind because the animals can be examined frequently without risking disturbances in cerebro-spinal fluid dynamics or tissue damage that would result from introduction of contrast media into the ventricular system. Our results and others reported earlier suggest that the dilated central canal acts as a kind of spontaneous CSF deviation route from the ventricles to the subarachnoid space. In spite of the tendency of the animals to recover in a clinical sense, the internal CSF space continued to expand; in cats the disease is progressive, a fact that is readily evident in follow-up CTs. This characteristic indicates that the spontaneous “shunt system” from the fourth ventricle through the dilated central canal to the spinal CSF spaces does not function well enough. Possible explanations for hydrocephalus compensation and the development of hydrosyringomyelia in experimental animals are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01795699
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  • 3
    Electronic Resource
    Electronic Resource
    Pattern of in vivo release of endogenous histamine in the mamillary body and the amygdala (1988)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 337 (1988), S. 53-57 
    Details
    ISSN: 1432-1912
    Keywords: Endogenous histamine release ; Mamillary body ; Medial amygdaloid nucleus ; Ultradian rhythm ; Suprachiasmatic nucleus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The mamillary body and the medial amygdaloid nucleus of cats anaesthetized with sodium pentobarbital were bilaterally and simultaneously superfused through push-pull cannulae with CSF and the release of endogenous histamine was determined in the superfusates. Collection of the superfusates in 10 min time periods revealed that histamine was rhythmically released in the two areas with frequencies of one cycle/90 min (mamillary body) or one cycle/135 min (medial amygdaloid nucleus). Collection of the superfusates in time periods of 2 min revealed the existence of an additional ultradian rhythm with a frequency of approximately one cycle/19 min in both areas. Bilateral lesions of the suprachiasmatic nucleus did not seem to influence the pattern of histamine release in the mamillary body and the medial amygdaloid nucleus, but the rate of histamine release was decreased in the mamillary body. It is concluded that the ultradian rhythms of histamine release in the mamillary body and the medial amygdaloid nucleus are not dependent on the integrity of the suprachiasmatic nucleus. The rate of histamine release in the mamillary body seems to be under the influence of excitatory neurons which originate from the suprachiasmatic nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169476
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  • 4
    Electronic Resource
    Electronic Resource
    Afferents to the lateral reticular nucleus from the oculomotor region (1988)
    Springer
    Anatomy and embryology 177 (1988), S. 277-283 
    Details
    ISSN: 1432-0568
    Keywords: Lateral reticular nucleus ; Oculomotor region ; Retrograde transport of WGA-HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By means of retrograde transport of the wheat germ agglutinin-horseradish peroxidase complex, afferent fibres to the lateral reticular nucleus from the oculomotor and accessory oculomotor nuclei were demonstrated in the cat. Small iontophoretic ejections were made into the main part of the lateral reticular nucleus from a ventral approach. Significant numbers of retrogradely labelled neurons were found bilaterally in all parts of the oculomotor nucleus. The majority was of small size and distributed along the dorsal and lateral boundaries of the nucleus. Some labelled neurons were located just outside these boundaries, in the periaqueductal gray and the adjacent mesencephalic reticular formation. Retrogradely labelled neurons were also found in the accessory oculomotor nuclei: The interstitial nucleus of Cajal featured a substantial number of labelled neurons. Some labelled neurons were consistently found also in the nucleus of the posterior commissure, but no labelled neurons were found in the nucleus of Darkschewitch. The labelled neurons in the interstitial nucleus of Cajal were of different sizes and located bilaterally, mainly in its rostral part. Caudal as well as rostral parts of the main lateral reticular nucleus appear to receive the descending afferents from the oculomotor region, but higher numbers of labelled neurons were found subsequent to ejections in the rostral part. The findings are discussed and some comments are made concerning the lateral reticular nucleus as a possible relay nucleus for oculomotor input to the cerebellum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00321138
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  • 5
    Electronic Resource
    Electronic Resource
    The accessory optic system of the rabbit, cat, dog and monkey: a whole-mount HRP study (1988)
    Springer
    Anatomy and embryology 177 (1988), S. 285-295 
    Details
    ISSN: 1432-0568
    Keywords: Accessory optic system ; Rabbit ; Cat ; Dog Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The three-dimensional fiber pathways of the accessory optic system in the rabbit, cat, dog and monkey were studied in whole-mounted preparations of the diencephalon and the midbrain, without sectioning, by anterograde labeling of retinal axons with horseradish peroxidase (HRP). HRP histochemical studies on alternate serial coronal sections were also performed. The rabbit accessory optic system exhibited two fasciculi (the inferior fasciculus, and the superior fasciculus consisting of the anterior fibers and the posterior fibers) and three terminal nuclei (the medial terminal nucleus, and the anterior and posterior porcions of the lateral terminal nucleus), but lacked the dorsal terminal nucleus. In the cat and dog, only the posterior fibers of the superior fasciculus were detected. The inferior fasciculus and the anterior fibers of the superior fasciculus were absent. The medial terminal nucleus and the posterior portion of the lateral terminal nucleus were commonly observed in the cat and dog. The cat accessory optic system possessed the dorsal terminal nucleus, and the dog accessory optic system possessed the anterior portion of the lateral terminal nucleus. The monkey (Macaca fuscata) accessory optic system consisted of the posterior fibers of the superior fasciculus, but blacked the inferior fasciculus and the anterior fibers of the superior fasciculus. Most of the posterior fibers terminated in the well-developed posterior portion of the lateral terminal nucleus located on the upper surface of the cerebral peduncle. A small number of posterior fibers projected to the poorly-developed medial terminal nucleus. Based on these findings, species differences in the mammalian accessory optic system were discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315835
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  • 6
    Electronic Resource
    Electronic Resource
    The feline oculomotor nucleus: morphological subdivisions and projection to the cerebellar cortex and nuclei (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 67-75 
    Details
    ISSN: 1432-0568
    Keywords: Retrograde transport of WGA-HRP ; Oculomotor nucleus ; Cerebellar nuclei ; Cerebellar cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cytoarchitecture of the feline oculomotor nucleus was examined in sections stained with thionin and neutral red. Five different subdivisions (caudal central, paramedian, ventral, dorsomedial and dorsolateral divisions) can be identified on each side of the midline. This observation is discussed, and our findings are compared to previous studies of the cytoarchitecture or central muscular representation of the oculomotor nucleus in which different subgroups have been distinguished. Implants or injections of the wheat germ agglutinin-horseradish peroxidase complex have revealed that all five subdivisions project to different parts of the cerebellar cortex and nuclei. Retrogradely labelled cells were found in the oculomotor nucleus in 18 cases following deposition of tracer in the fastigial and interposed nuclei and certain regions of the anterior, posterior and flocculonodular lobes. The projection is bilateral and appears to have its main termination in flocculus. It originates from small neurons, especially from those located along the dorsal border of the oculomotor nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305016
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  • 7
    Electronic Resource
    Electronic Resource
    The distribution of infrahyoid motoneurons in the cat: a retrograde horseradish peroxidase study (1988)
    Springer
    Anatomy and embryology 177 (1988), S. 445-450 
    Details
    ISSN: 1432-0568
    Keywords: Motoneurons ; Infrahyoid muscles ; Spinal cord ; HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of cell bodies and the peripheral course of axons of infrahyoid motoneurons were examined in the cat by the retrograde horseradish peroxidase method after application of the enzyme to the peripheral nerve branches supplying the infrahyoid muscles. Infrahyoid motoneurons were observed to constitute a slender cell column, which extended from a level of the caudal part of the hypoglossal nucleus usually to the most caudal level of the C1 cord segment, or occasionally to the lower levels of the C2 cord segment. The cell column was located immediately lateral to that of motoneurons of the spinal accessory nerve. In the cell column, thyrohyoid motoneurons were distributed in the medulla oblongata; sternohyoid motoneurons were located somewhat more cranially than sternothyroid motoneurons in the medulla oblongata and cervical cord. However, the level of craniocaudal distribution of thyrohyoid, sternohyoid or sternothyroid motoneurons highly overlapped. The experiments involving severance of the hypoglossal and/or cervical nerves indicated that axons of thyrohyoid and sternohyoid motoneurons passed via the roots of both hypoglossal and C1 nerves, that axons of sternohyoid motoneurons passed via the C1 nerve roots, and that axons of infrahyoid motoneurons innervating the conjugated part of the sternohyoid and sternothyroid muscles passed usually via the C1 nerve roots, or occasionally via the roots of both C1 and C2 nerves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00304742
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  • 8
    Electronic Resource
    Electronic Resource
    Cerebellar cortical and nuclear afferents from the Edinger-Westphal nucleus in the cat (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 59-65 
    Details
    ISSN: 1432-0568
    Keywords: Retrograde transport of WGA-HRP ; Edinger-Westphal nucleus ; Cerebellar nuclei ; Cerebellar cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cerebellar projection from the Edinger-Westphal nucleus was studied in the cat by means of retrograde transport of the wheat germ agglutinin-horseradish peroxidase complex. The present findings give evidence that the flocculus is the main terminal area. However, small tracer implants and injections into various parts of the cerebellar nuclei and cortex revealed projections also to the fastigial and interposed nuclei and to most parts of the anterior and posterior lobe cortices. The projecting neurons are small and located bilaterally throughout the Edinger-Westphal nucleus. No topical differences between the projections to different parts of the cerebellum were found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305015
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  • 9
    Electronic Resource
    Electronic Resource
    Routes of entry into the cerebellum of spinocerebellar axons from the lower part of the spinal cord (1988)
    Springer
    Experimental brain research 72 (1988), S. 543-561 
    Details
    ISSN: 1432-1106
    Keywords: Spinocerebellar neurons ; Cerebellar peduncles ; Axonal course ; Horseradish peroxidase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Among the newly discovered spinocerebellar cell groups, those at lumbar and more caudal levels of the cat's spinal cord were studied with regard to which of the two cerebellar peduncles, the restiform body or the superior cerebellar peduncle, is used by their axons. Bilateral injections with horseradish peroxidase were made into either of the anterior lobe or the posterior cerebellar termination area for spinocerebellar fibers, following unilateral transections of either the superior cerebellar peduncle or the restiform body, combined with low contralateral transections of the lateral and ventral funiculi. Following transection of the superior cerebellar peduncle, labeled neurons were found ipsilateral to the transection in the column of Clarke and in laminae IV–VI at L 3–L 7. Contralaterally, labeled neurons were found in the ventromedial nucleus and lamina VIII of the ventral horn in the sacro-coccygeal segments and in the medial part of lamina VII at L 6 and more caudal levels. All these neurons were regarded as sending their axons through the restiform body. Following transection of the restiform body, labeled neurons were found in the following areas contralateral to the transection: the dorsolateral nucleus of the L 3–L 6 segments, the lateral part of lamina VII at L 3–L 5/6, the medial part of lamina VII in L 6 and more caudal segments, and the ventrolateral nucleus of L 4–L 5. Ipsilaterally, labeled neurons were found in lamina VIII at L 4–L 6. All these neurons were regarded as sending their axons through the superior cerebellar peduncle. In addition to new information about the peduncular routes of spinocerebellar neurons, the study has given confirming evidence as to the crossing conditions for different spinocerebellar cell groups. The findings should be useful in future studies on the organization of the spinocerebellar systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250600
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  • 10
    Electronic Resource
    Electronic Resource
    Collateral projections of neurons from the lower part of the spinal cord to anterior and posterior cerebellar termination areas (1988)
    Springer
    Experimental brain research 72 (1988), S. 562-576 
    Details
    ISSN: 1432-1106
    Keywords: Spinocerebellar neurons ; Cerebellar cortex ; Fluorescent tracers ; Double labeling ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The collateral projections of spinocerebellar neurons located in the L 2 to Ca 1 spinal segments in the cat were investigated by retrograde fluorescent double labeling technique. Rhodamine labeled latex microspheres (Rm) and Fast Blue (FB) were used for injections into the cerebellum in 8 cats. Two additional cats, with injections of Fluoro-Gold (FG) combined with Rm were excluded because lipofuchsin autofluorescence obscured the labeling. After injections with one tracer unilaterally in the paramedian lobule and another tracer bilaterally in the anterior lobe, double labeled neurons were found on the side of the paramedian lobule injection in the column of Clarke at L 2–L 4, laminae IV–VI at L 2–L 5 and the dorsolateral nucleus at L 2–L 6. After bilateral injections of one tracer in lobule VIII B and another in the anterior lobe, double labeled neurons were found bilaterally in the column of Clarke at L 2–L 4, laminae IV–VI at L 2–L 5, the medial part of lamina VII at L 6–L 7 and in certain cell groups at sacro-coccygeal levels. Neurons in the lateral part of lamina VII at L 3–L 5 and the ventrolateral nucleus of L 4–L 5 were labeled exclusively from injections in the anterior lobe. The findings indicate that spinocerebellar neurons at lumbar and more caudal levels of the cat spinal cord have different projection patterns in the cerebellum. A certain number of neurons which project to the anterior lobe have divergent axon collaterals supplying also the posterior vermis and/or the paramedian lobule. Other neurons project to the anterior or to the posterior lobe only.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250601
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  • 11
    Electronic Resource
    Electronic Resource
    Properties and localization of the anterior semicircular canal-activated vestibulocollic neurons in the cat (1988)
    Springer
    Experimental brain research 71 (1988), S. 345-352 
    Details
    ISSN: 1432-1106
    Keywords: Anterior semicircular canal ; Vestibular nuclei ; Vestibulo-collic ; Neck motoneuron ; Unitary EPSP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Unit activites of secondary vestibular neurons that selectively responded to stimulation of the anterior semicircular canal nerve (ACN) were recorded extracellularly in the anesthetized cat. Axonal pathways and projections in the spinal cord of the ACN-activated neurons were examined by recording their antidromic responses to stimulation of the lateral and medial vestibulospinal tracts (LVST and MVST), and the bilateral neck extensor motoneuron pools in the C1segment (C1dorsal rami [DR] motoneuron pools). In order to determine whether the neurons had ascending axon collaterals to the extraocular motoneurons, the contralateral (c-) inferior oblique (IO) motoneuron pool was also stimulated. Twenty-seven neurons sent their axons to the ipsilateral (i-) C1DR motoneuron pool via the LVST without any projection to the extraocular motoneuron pool. All the cells except one were located in the ventral part of the lateral vestibular nucleus. This pathway produced monosynaptic EPSPs with short time-to-peak and short half-width in C1DR motoneurons (16/16 motoneurons). Eight neurons sent axons to the i-C1DR motoneuron pool via the MVST without any to the extraocular motoneuron pool. Cell somata were located in the descending nucleus or in the ventral part of the lateral nucleus. These neurons did not produce postsynaptic potentials (PSPs) in any C1DR motoneurons. All thirty-five neurons sending axons to the c-C1DR motoneuron pool have ascending axon collaterals to the c-IO motoneuron pool.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247494
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  • 12
    Electronic Resource
    Electronic Resource
    The organization of receptive fields in area 18 neurones of the cat varies with the spatio-temporal characteristics of the visual stimulus (1988)
    Springer
    Experimental brain research 71 (1988), S. 1-7 
    Details
    ISSN: 1432-1106
    Keywords: Area 18 ; Receptive field ; Velocity ; Spatial frequency ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The spatial frequency tuning curves of neurones of area 18 depend upon the velocity of the visual stimulus. The higher the velocity the lower the spatial frequencies to which the cell is tuned. Since in area 17 the size of the cell receptive field is inversely related with the optimal spatial frequency to which the cell responds, we have investigated whether the shift of the optimal spatial frequency with the velocity corresponds to a “change” in the receptive field size. We recorded extracellularly from neurones in area 18; for each cell we selected two gratings, one of high spatial frequency drifting at low velocity and another of low spatial frequency drifting at high velocity to which the cell gave comparable responses. The results show that the masking of the cells receptive field which abolishes the response to the high frequency low velocity grating does not prevent the cell from responding to the low frequency high velocity grating. We conclude that the size of the receptive field of neurones in area 18 depends upon the characteristics (spatial frequency and velocity) of the visual stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247517
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  • 13
    Electronic Resource
    Electronic Resource
    Topographic relations between ocular dominance and orientation columns in the cat striate cortex (1988)
    Springer
    Experimental brain research 71 (1988), S. 33-46 
    Details
    ISSN: 1432-1106
    Keywords: Columns ; Visual cortex ; Orientation ; Ocular dominance ; Maps ; Cat ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the visual cortex of four adult cats ocular dominance and orientation columns were visualized with (3H)proline and (14C)deoxyglucose autoradiography. The two columnar systems were reconstructed from serial horizontal sections or from flat-mount preparations and graphically superimposed. They share a number of characteristic features: In both systems the columns have a tendency to form regularly spaced parallel bands whose main trajectory is perpendicular to the border between areas 17 and 18. These bands frequently bifurcate or terminate in blind endings. The resulting irregularities are much more pronounced in the ocular dominance than in the orientation system. The periodicity of the columnar patterns was assessed along trajectories perpendicular to the main orientation of the bands and differed in the two columnar systems. The spacing of the ocular dominance stripes was significantly narrower than the spacing of orientation bands. The mean periodicity of a particular columnar system was virtually identical in the two hemispheres of the same animal but it differed substantially in different animals. However, the spacing of orientation columns covaried with that of the ocular dominance columns, the ratios of the mean spacings of the two columnar systems being similar in the four cats. The superposition of the two columnar systems revealed no obvious topographic relation between any of the organizational details such as the location of bifurcations, blind endings and intersections. We suggest the following conclusions: 1. The developmental processes generating the two columnar systems seem to obey the same algorithms but they act independently of each other. 2. The space constants of the two systems are rigorously specified and appear to depend on a common variable. 3. The main orientation of the bands in both columnar systems is related to a) the representation of the vertical meridian, b) the anisotropy of the cortical magnification factor, and c) the tangential spread of intracortical connections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247520
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  • 14
    Electronic Resource
    Electronic Resource
    Automatic postural responses in the cat: responses of hindlimb muscles to horizontal perturbations of stance in multiple directions (1988)
    Springer
    Experimental brain research 71 (1988), S. 93-102 
    Details
    ISSN: 1432-1106
    Keywords: Postural reflexes ; Unexpected postural perturbations ; Electromyographic activity ; Muscle synergies ; Motor control ; Hindlimb muscles ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of the direction of unexpected horizontal perturbations of stance on the organization of automatic postural responses was studied in cats. We recorded EMG activity in eight proximal and distal muscles of the hindlimb along with vertical forces imposed by the limbs in awake behaving cats while they stood on an hydraulic platform. Postural responses to motion of the platform in 16 different horizontal directions were recorded. Vertical force changes were consistent with passive shifts of the center of mass and active correction of stance by the animals. When the perturbation was in the sagittal plane, vertical force changes began about 65 ms following initial platform movement. When the perturbation contained a component in the lateral direction, latency for vertical force changes was about 25 ms and an inflection in the vertical force trace was observed at 65 ms. No EMG responses were observed with latencies that were short enough to account for the early force component and it was concluded that this force change was due to passive shifts of the center of mass. The amplitude of the EMG responses of each muscle recorded varied systematically as perturbation direction changed. The directions for which an individual muscle showed measurable EMG activity were termed the muscle's “angular range of activation.” No angular range of activation was oriented strictly in the A-P or lateral directions. Most muscles displayed angular ranges of activation that encompassed a range of less than 180°. Onset latencies of EMG responses also varied systematically with perturbation direction. The amplitude and latency relationships between muscles, which made up the organization of postural responses, also varied systematically as perturbation direction was changed. This result suggests that direction of perturbation determines organizational makeup of postural responses, and for displacements in the horizontal plane, is considered a continuous variable by the nervous system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247525
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  • 15
    Electronic Resource
    Electronic Resource
    Spared-root deafferentation of a cat's hindlimb: hierarchical regulation of pathways mediating recovery of motor behavior (1988)
    Springer
    Experimental brain research 73 (1988), S. 329-342 
    Details
    ISSN: 1432-1106
    Keywords: Dorsal roots ; Locomotion ; Sprouting ; Cat ; Plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous studies showed that after complete hindlimb deafferentation in cats, the ipsilateral descending pathways mediated recovery of overground, goal-directed locomotion and accurate placement of the deafferented limb. In the present study deafferentations sparing one dorsal root (L6) were performed to see if the descending systems would still be responsible for the recovery. The partially deafferented hindlimb is initially impaired in postural reflexes and accurate placement during locomotion but considerable recovery occurs. A similar pattern of severe impairment and subsequent recovery is observed in cats in which the only lesion is L1 hemisection. When a hemisection is added 6 months later to chronic spared-root deafferentation the recovery (from the latter lesion) is temporarily reversed but the animals recover again in a fashion similar to that after hemisection alone. Since there is no recovery of overground locomotion when hemisection is added to complete deafferentation but there is when deafferentation is incomplete, the descending pathways apparently are not responsible for maintaining the recovery when one dorsal root is spared as they are when all are cut. The results suggest that a competitive or hierarchical control over residual systems may regulate recovery of motor function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248225
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  • 16
    Electronic Resource
    Electronic Resource
    Axonal trajectories of posterior canal-activated secondary vestibular neurons and their coactivation of extraocular and neck flexor motoneurons in the cat (1988)
    Springer
    Experimental brain research 70 (1988), S. 181-191 
    Details
    ISSN: 1432-1106
    Keywords: Axonal branching ; Vestibulo-ocular ; Vestibulo-collic ; Neck motoneurons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Unit activities of 148 secondary vestibular neurons related to the posterior semicircular canal were recorded extracellularly in anesthetized cats. Axonal projections of these neurons were examined by their antidromic responses to stimulation of the excitatory target motoneurons of the contralateral (c-) inferior rectus muscle (IR) and bilateral (bi-) motoneuron pools of longus capitis muscles, neck flexors, in the C1 segment (C1LC). The neurons were classified into 4 groups according to their axonal projections. The first group of neurons, termed vestibulo-oculo-collic (VOC) neurons, sent axon collaterals both to the c-IR motoneuron pool and to the c-C1LC motoneuron pool. The majority of them (72%) were located in the descending nucleus. The second group of neurons were termed vestibuloocular (VO) neurons and sent their axons to the c-IR motoneuron pool but not to the cervical cord. Most of them (86%) were located in the medial nucleus. The third group of neurons, termed vestibulo-collic (contralateral) (VCc) neurons, sent axons to the cC 1LC motoneuron pool via the contralateral ventral funiculus but not to the oculomotor nuclei. They were mostly (75%) found in the descending nucleus. The last group of neurons were vestibulo-collic (ipsilateral) (VCi) neurons, which gave off axons to the ipsilateral (i-) C1LC motoneuron pool via the ipsilateral ventral funiculus but not to the oculomotor nuclei. One of them also sent an axon collateral to the c-C1LC motoneuron pool. The majority of them (74%) were located in the ventral part of the lateral nucleus. It was also observed in some of the VOC and VCi neurons that they produced unitary EPSPs in the c-C1LC and i-C1LC motoneurons, respectively. Their synaptic sites were estimated to be on the cell somata and/or proximal dendrites of the motoneurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271859
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  • 17
    Electronic Resource
    Electronic Resource
    Stimulus contrast and visual cortical lesions (1988)
    Springer
    Experimental brain research 72 (1988), S. 191-194 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Ablation ; Orientation discrimination ; Contrast ; Redundancy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intact animals can make fine orientation discriminations over a wide range of contrasts. After ablation of area 17 deficits in orientation discrimination are observed only at low contrast. The relevance of this finding for the design of sensitive ablation experiments is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248515
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  • 18
    Electronic Resource
    Electronic Resource
    Distribution and projection of single units in the cat preoptic region responding to stimulation of the medial amygdala (1988)
    Springer
    Experimental brain research 70 (1988), S. 449-454 
    Details
    ISSN: 1432-1106
    Keywords: Preoptic area ; Amygdala ; Medial forebrain bundle ; Medial basal hypothalamus ; LH ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal responses were recorded extracellularly in the preoptic region of 11 male castrate cats following stimulation in the ‘medial’ group of amygdalar nuclei (medial, basomedial, basolateral). The latency of responses varied with the site of stimulation and could be explained if connections to the preoptic region were made through both the stria terminalis and the ventral amygdalofugal pathway. Projection of 13% of orthodromically excited preoptic units to the medial basal hypothalamus was established by collision tests following stimulation in these regions. The amygdalar excitation was probably exerted through the amygdalofugal pathway. In 5/6 cats the amygdalar stimulation was successfully used to raise plasma LH levels. In one cat no preoptic units projecting to the medial basal hypothalamus were found and in the cat which failed to increase plasma LH in response to amygdala stimulation, 5 such units were found. We conclude the pathway from the amygdala through the preoptic region to the hypothalamus may not be the way in which amygdalar stimulation affects LH release in the cat. Projection of 10% of orthodromically excited preoptic units in the medial forebrain bundle was established by collision tests in 3 cats. These identified units were driven from amygdalar sites thought to project to the preoptic region by ventral amygalofugal pathways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247592
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  • 19
    Electronic Resource
    Electronic Resource
    Dopamine and serotonin in cat retina: electroretinography and histology (1988)
    Springer
    Experimental brain research 71 (1988), S. 231-240 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Retinal electrophysiology ; Electroretinogram ; Neurotransmitters ; Dopamine ; Serotonin ; Aminophosphonobutyric acid (APB)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Anatomical structures of the cat retina were related to functional changes induced by the application of dopaminergic and serotonergic substances. We report on the contribution of dopaminergic and serotonin accumulating retinal neurones to retinal activity as reflected by the electroretinogram. The effect of dopaminergic neurones was investigated by the application of the neurotoxin 6-hydroxydopamine (6-OHDA) which is known to destroy dopaminergic neurones, and injections of either serotonin (5-HT) or the analogue 5,6-dihydroxytryptamine (5,6-DHT) were used to monitor the effects of indoleamines. In control experiments aminophosphonobutyric acid (APB), an agonist of glutamate transmission, was injected. Conventional immunohistochemical methods identified dopaminergic and serotonin accumulating neurones, and the electrophysiological data obtained from the same animals were related to the anatomical structures influenced by the respective substances. Destruction of dopaminergic amacrine cells by 6-OHDA increased the ERG b-wave amplitude. Accumulation of indoleamines by certain amacrine cells also caused an increase of the ERG b-wave. However, intravitreal injection of APB completely blocked the bwave. The data show that ERG mass responses can be used to monitor transmitter-specific effects on retinal circuitry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247483
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  • 20
    Electronic Resource
    Electronic Resource
    Distribution of opiate receptors within visual structures of the cat brain (1988)
    Springer
    Experimental brain research 73 (1988), S. 523-532 
    Details
    ISSN: 1432-1106
    Keywords: Opiate ; Receptor ; Vision ; Cat ; Mu ; Kappa ; Delta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distributions of μ, δ, and χ opiate receptors within visual regions in the cat cortex, thalamus and midbrain were determined by in vitro autoradiography. The overall distribution of receptors was examined using [3H]-etorphine, a ligand that nonselectively labels all types of opiate receptors. [3H]-[D-Ala2, N-Me-Phe4, Gly(ol)5]-enkephalin (DAGO) was used to selectively label μ receptors, [3H]-[D-Pen2,5]-enkephalin (DPDPE) for δ receptors, and [3H]-bremazocine for χ receptors. Each of the areas examined showed clear opiate receptor binding with [3H]-etorphine and a differential distribution of μ, δ, and χ receptors. Compared to other cortical regions, opiate binding in layers 3 and 4 of areas 17 and 18 was sparse. In the adjacent areas a more uniform distribution across layers was observed. The density of χ opiate receptors was greater in cortex than in subcortical structures, whereas the reverse was the case for μ receptors. Nevertheless, all three types of opiate receptors were found in the ventral and dorsal subdivisions of the lateral geniculate (LGN), the pulvinar complex, and the suprageniculate nucleus. In the midbrain, the superficial layers of the superior colliculus were heavily labelled with the μ, receptor ligand, and modestly with the χ ligand. Compared with other midbrain and diencephalic areas, δ binding was low in the superior colliculus. These results suggest that the diverse effects of opiates on visual perception are mediated by the unique distributions of opiate receptor types throughout the visual areas in the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406610
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  • 21
    Electronic Resource
    Electronic Resource
    Binocular interaction in the perigeniculate nucleus of the cat (1988)
    Springer
    Experimental brain research 69 (1988), S. 497-508 
    Details
    ISSN: 1432-1106
    Keywords: Binocular interaction ; Perigeniculate nucleus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have recorded from single cells in the perigeniculate nucleus (PGN) of the cat to determine their response properties. Quantitative tests have been conducted with sinusoidal gratings. Using optimal stimulus parameters, determined monocularly, we explored binocular interaction by varying the relative phase between dichoptically presented gratings. Monocularly, cells exhibit varying degrees of response specificities with respect to stimulus orientation and spatial frequency. Binocularly, we have identified six types of response. The most prominent, type 1, found for half the cells, is phase-specific binocular interaction at the fundamental frequency component of the drifting grating. For these cells, mean response rate is independent of interocular phase. The remaining types of binocular responses involve varying degrees of interaction at different harmonic components. For a quarter of the sample, no binocular interaction was observed. To investigate the role of cortical input to PGN, visual cortex was removed from some cats. Subsequent study of PGN cells indicated that response properties were generally similar to those found in intact animals. We conclude that PGN response properties are determined primarily by subcortical inputs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247304
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  • 22
    Electronic Resource
    Electronic Resource
    Relationships between nucleus medialis dorsalis, pericruciate cortex, ventral tegmental area and nucleus accumbens in cat: an electrophysiological study (1988)
    Springer
    Experimental brain research 69 (1988), S. 559-566 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Nucleus medialis dorsalis ; Ventral tegmental area ; Nucleus accumbens ; Pericruciate cortex ; Attentional mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In anaesthetized cats, single units were recorded from the ventrolateral part of n. medialis dorsalis (MD) of the thalamus. Cells were tested for their ortho- or antidromic short latency responses to single electrical shocks applied to the pericruciate cortex (PCx) and to either the mesencephalic ventral tegmental area (VTA) or the nucleus accumbens (ACC). Some reciprocal direct connections were thus shown to exist between MD and PCx, i.e. a cortical area posterior to the main classical MD “prefrontal” projection zone. Reciprocal direct connections were also identified physiologically between MD and VTA and between MD and ACC. Coupled stimulations showed that some MD cells could serve as a relay for a pathway from VTA to cortex, others for a reciprocal pathway from PCx to VTA, and still others, for a pathway from PCx to ACC. These findings are compared to previous — mostly anatomical — data obtained in other species, mainly rat. Their functional meaning is also discussed, in the light of previous results on the roles of MD, VTA and ACC in the control of immobility during focused attentive behaviour in cat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247309
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  • 23
    Electronic Resource
    Electronic Resource
    Evidence for a nicotinic component to the actions of acetylcholine in cat visual cortex (1988)
    Springer
    Experimental brain research 73 (1988), S. 553-568 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Visual cortex ; Acetylcholine ; Nicotinic receptors ; Iontophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Radioligand binding assays, receptor autoradiography and iontophoresis have been used to look for evidence of a nicotinic component to the actions of acetylcholine in cat visual cortex. [3H]Nicotine bound to a uniform population of high affinity binding sites in cat primary visual cortex. This binding was inhibited by nicotine agonists and antagonists but not muscarinic antagonists. The concentration of nicotinic binding sites was about 10% of that of muscarinic binding sites measured with [3H]N-methylscopolamine. The muscarinic sites were resolved into M1 and M2 subtypes. Quantitative receptor autoradiography showed that there were muscarinic sites in all layers, although they were least abundant in layer IV of area 17. In contrast, the nicotinic sites were most concentrated in layer IV in area 17. The concentration of this labelling was reduced at the 17/18 border and also at the 18/19 border. Layer I of the cingulate and suprasylvian gyri were also labelled. Electrolytic lesions of the lateral geniculate nucleus (LGN) led to a loss of nicotinic binding sites in layer IV of area 17, indicating that these sites are most likely located on the LGN terminals. Iontophoresis of mecamylamine, a nicotinic antagonist, decreased evoked responses in visual cortex, providing evidence that the [3H]nicotine binding sites are functional receptors and suggesting that the release of acetylcholine onto these receptors on the LGN terminals facilitates the input of visual information into visual cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406614
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  • 24
    Electronic Resource
    Electronic Resource
    Vestibulo-ocular reflex adaptation in cats before and after depletion of norepinephrine (1988)
    Springer
    Experimental brain research 69 (1988), S. 509-521 
    Details
    ISSN: 1432-1106
    Keywords: Vestibulo-ocular reflex ; Cat ; Norepinephrine ; Neuronal adaptation ; 6-hydroxydopamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The vestibulo-ocular reflex (VOR) operates to stabilize the eyes in space during movements of the head. The system has been described as having a gain of approximately -1 since stimulation of the semi-circular canals brought about by head movements will have the effect of causing the eyes to rotate an equal amount in the opposite direction. Change in the gain of the VOR has been put forth as a model to study plasticity in the central nervous system. Since numerous studies have implicated norepinephrine (NE) in neuroplasticity and modifiability of neural circuits, we attempted to determine the effect of NE depletion (via 6-hydroxydopamine (6-OHDA) intra-cisternal injection) on the modifiability of the VOR. We have found that cats increase the gain of their VOR over a four hour period when rotated in the horizontal plane in a manner equal but opposite to the rotation of a surrounding opto-kinetic drum. The entire group of animals manifests a statistically significant decrement in their ability to increase VOR gain when central stores of norepinephrine are depleted via intra-cisternal injection of 6-OHDA. Individual animals manifest a wide variety of gain changes (0.98 to 1.62). We have found that there were two groups of cats — high and low gain modifiers. The greatest reduction in VOR gain increase after NE depletion was observed in the high gain modifiers. No difference was observed in the low gain modifiers. These same animals tested for VOR modification after amphetamine injection, produced similar results. Alertness during the VOR modification task, as estimated by saccadic eye movement counts, was unchanged after NE depletion. NE levels, measured by HPLC-EC, after depletion were reduced to the greatest extent in the cerebellum. There was also a substantial reduction of NE in the visual cortex with less of a reduction in the brain stem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247305
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  • 25
    Electronic Resource
    Electronic Resource
    Voiced calls evoked by hypothalamic stimulation in the cat (1988)
    Springer
    Experimental brain research 71 (1988), S. 21-32 
    Details
    ISSN: 1432-1106
    Keywords: Voiced vocalization ; Hypothalamic stimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Voiced vocalizations evoked by hypothalamic stimulation were studied in a series of six awake adult cats. Electrical stimulation was found to evoke vocalizations at numerous sites within the hypothalamus, ranging from A+8 to A+16. Regions showing the largest number of responsive sites were the preoptic region, the ventromedial area, the perifornical region, the lateral and the dorso-medial hypothalamus. The form of the evoked calls was generally similar to the spontaneous calls of the same animal. Call latency, duration, and intensity were not significantly affected by changes in stimulus intensity or duration but all three of these call parameters were significantly affected by changes in stimulus frequency. In general, call latency was longest at sites in the rostral hypothalamus and shortest at sites in the caudal hypothalamus. This study is the first to investigate systematically voiced call producing areas in the hypothalamus of awake cats and to document similarities between these calls and spontaneously produced voiced calls.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247519
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  • 26
    Electronic Resource
    Electronic Resource
    Effects of convergent strabismus on spatio-temporal response properties of neurons in cat area 18 (1988)
    Springer
    Experimental brain research 72 (1988), S. 264-278 
    Details
    ISSN: 1432-1106
    Keywords: Convergent strabismus ; Cat ; Area 18 ; Temporal properties ; Contrast sensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single-cell recording experiments were carried out to determine whether rearing kittens with surgically induced convergent strabismus (esotropia) alters the development of receptive field (RF) properties of neurons in area 18. In agreement with previous work on kittens with divergent strabismus (exotropia), there was a marked loss of binocularly driven cells in area 18 of esotropic cats. In contrast to the striate cortex of strabismic cats, the spatial properties of area 18 neurons, including receptive-field size and spatial frequency tuning, did not differ from those in normal controls. On the other hand, we found that contrast thresholds, measured at an optimal spatial frequency, were significantly elevated, and that the contrast gain in many cells was reduced in strabismic cats. These deficits were observed in both eyes, though the cells dominated by the deviating eye had a lower response amplitude at all contrasts. Furthermore, temporal frequency tuning curves were abnormal in strabismic cats in that the optimal frequencies and temporal resolutions were shifted to lower values. These effects were also bilateral. Velocity tuning, measured with a high-contrast bar stimulus, revealed that area 18 neurons in strabismic cats were unable to respond to very high velocities compared to normals. This reduced response was more severe when measured with the deviating eye in spite of the bilateral nature of the deficit. Finally, latencies to electrical stimulation of the optic chiasm or the optic radiation were significantly longer in strabismic cats. The magnitude of these effects was virtually the same for both eyes. From these observations, we conclude that the temporal properties of area 18 neurons, particularly the cells abilities to follow fast temporal modulations, are affected by raising kittens with surgically induced convergent strabismus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250249
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  • 27
    Electronic Resource
    Electronic Resource
    Neural site of strabismic amblyopia in cats: X-cell acuities in the LGN (1988)
    Springer
    Experimental brain research 72 (1988), S. 503-509 
    Details
    ISSN: 1432-1106
    Keywords: Strabismic amblyopia ; Cat ; Lateral geniculate nucleus ; Acuity ; X-cell ; VEP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The acuities of X-cells from the dorsal lateral geniculate nucleus (LGN) were measured in five cats raised with a convergent strabismus, surgically induced by tenotomy. The acuities of cells driven by the strabismic eye were not significantly different from the acuities of cells driven by the non-deviating eye over the range of eccentricities in the visual field studied (from the area centralis to over 20°). The data were also similar to X-cell acuities in the LGN of 3 normal cats. Lowered acuities of LGN X-cells driven by the deviating eye of an esotropic cat in which the strabismus was created by myectomy confirm a previous finding of a retinal locus of amblyopia associated with that preparation. In contrast, the results here implicate the visual cortex as the initial site of the deficit in spatial processing in amblyopia arising from tenotomy strabismus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250595
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  • 28
    Electronic Resource
    Electronic Resource
    The contribution of the horizontal semicircular canals to the response to off-vertical-axis rotation in the cat (1988)
    Springer
    Experimental brain research 71 (1988), S. 147-152 
    Details
    ISSN: 1432-1106
    Keywords: Eye movements ; Vestibulo-ocular reflex ; Otoliths ; Off-vertical-axis rotation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The response to off-vertical-axis rotation (OVAR) was measured in cats under circumstances in which the signals from the horizontal semicircular canals and otoliths were opposed. Opposition was achieved by sudden acceleration or deceleration during constant velocity OVAR. The degree of opposition was expressed as a canal/otolith ratio where a ratio of unity indicated agreement. For a canal/otolith ratio of 1, the OVAR gain (eye velocity/ stimulus velocity) was 0.73 (±0.13). The steady-state OVAR response was, however, reduced if the canals and otoliths were opposed. The reduction depended on the degree of opposition with a fall-off of 0.15 gain/(unit of canal/otolith ratio). These findings are discussed with respect to the central velocity store and the mechanism underlying the generation of the OVAR response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247529
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  • 29
    Electronic Resource
    Electronic Resource
    Excitatory and inhibitory postsynaptic potentials in cat hypoglossal motoneurons during swallowing (1988)
    Springer
    Experimental brain research 71 (1988), S. 262-272 
    Details
    ISSN: 1432-1106
    Keywords: Swallowing ; Synaptic potential ; Hypoglossal motoneuron ; Extrinsic tongue muscle ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The postsynaptic potentials produced in cat genioglossus and styloglossus motoneurons (GG- and SG-Mns) during swallowing were studied. During swallowing elicited by placing water on the dorsum of the tongue, the GG-muscle discharged for 80–210 ms (mean±S. D. 123±31 ms, N=59) and was abruptly suppressed, and the SG-muscle began discharging in synchrony with the GG-muscle and discharged for 200–360 ms (mean+ S. D. 247±36 ms, N=59). The GG and the SG-Mns were identified if unitary muscle activity followed the induced spike of the motoneuron one-for-one. During swallowing, excitatory postsynaptic potentials (EPSPs) were evoked in the SG-Mns regardless of the respiratory drive on the SG-Mns, and inhibitory postsynaptic potential (IPSP) or EPSP-IPSP was evoked on the GG-Mns regardless of the respiratory drive on the GG-Mns. By increasing the intracellular concentration of chloride ions, the IPSP elicited in the GG-Mn during swallowing was turned into a depolarizing potential. In immobilized cats, a depolarizing potential and a depolarizing-hyperpolarizing potential sequence was evoked successively on a tongue retractor motoneuron and a tongue protruder motoneuron by repetitive electrical stimulation of the superior laryngeal nerve.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247486
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  • 30
    Electronic Resource
    Electronic Resource
    Nystagmus induced by off-vertical rotation axis in the cat (1988)
    Springer
    Experimental brain research 73 (1988), S. 78-90 
    Details
    ISSN: 1432-1106
    Keywords: Otoliths ; Nystagmus ; Labyrinth ; Eye movements ; Velocity storage mechanism ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1) In the alert cat, nystagmus induced by off-vertical axis rotation (OVAR) was recorded following steps in head velocity or ramps of velocity at constant acceleration below canal threshold. Dependence of nystagmus characteristics on tilt angle of rotation axis and head velocity was studied. Similar results were obtained with both types of stimulation. 2) Mean and modulation amplitude of horizontal eye velocity increased with tilt angle in the range 0–30 degrees. 3) Both variables increased also with head velocity, but with different trends, probably because they are set by different mechanisms. When head rotational velocity was increased above 80°/s, mean eye velocity progressively decreased to zero. 4) In spite of variations from one animal to another, some regularity was observed in the phase of eye velocity modulation. In several cases, a reduction in phase lead of eye velocity with respect to conventional origin of phases (nose-down position) was observed when head velocity increased. 5) Time constant of post-OVAR nystagmus decreased with the tilt angle of the rotation axis from gravity, but not with the orientation of the head with respect to rotation axis. 6) The results could be accounted for by a general equation describing the vestibulo-ocular reflex, provided that estimates of kinematic variables of head movement (head rotational and translational velocities), and visual target distance could be computed by the Central Nervous System.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00279663
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  • 31
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    Effects of the dopamine antagonists haloperidol and domperidone on the normoxic ventilatory response to CO2 in cats (1988)
    Springer
    Pflügers Archiv 411 (1988), S. 278-282 
    Details
    ISSN: 1432-2013
    Keywords: Peripheral chemoreceptors ; Central chemoreceptors ; Control of respiration ; Dopamine ; Haloperidol ; Domperidone ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the effects of the dopamine antagonists haloperidol and domperidone on the ventilatory response following square-wave changes in end-tidal CO2 during normoxia in chloralose-urethane anaesthetized cats. In 7 cats these responses were measured before (control, 28 runs) and after the administration of 1 mg/kg haloperidol i.v. (26 runs) and in 8 other cats before (39 runs) and after 0.5 mg/kg domperidone i.v. (34 runs). Each response was separated into a slow central and a fast peripheral part by fitting two exponential functions to the measured ventilation. These functions have as parameters a CO2 sensitivity, a time constant, a time delay and an apnoeic threshold B (extrapolated PETCO2 of the steady-state response curve at zero ventilation). Haloperidol significantly diminished the peripheral (Sp) and the central (Sc) ventilatory sensitivity to CO2 and the B-value (P〈0.001). The ratio Sp/Sc, the time constants and the time delays were not significantly changed. Domperidone only diminished the B-value significantly (P〈0.001). Since domperidone does not readily cross the blood-brain barrier, its effect was a CO2 independent increase of the ventilation mediated by the peripheral chemoreceptors. Haloperidol exhibited, besides the peripheral stimulatory effect a depressant central effect due to an action on the central integrative structure, resulting in a proportional decrease of Sp and Sc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00585115
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  • 32
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    Electronic Resource
    Apomorphine-induced limb flicks in cats: the role of dopamine receptors located outside the blood-brain barrier (1988)
    Springer
    Psychopharmacology 95 (1988), S. 268-270 
    Details
    ISSN: 1432-2072
    Keywords: Aminotetralin ; Apomorphine ; Cat ; Emesis ; Limb flicks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Apomorphine-induced limb flicks in cats have been ascribed to a central dopamino-mimetic action of the drug. In these experiments we investigated the role of receptors located outside the blood-brain barrier (BBB) in the induction of limb flicking. Domperidone, a dopamine-receptor blocker which does not readily pass through the BBB, antagonised the induction of limb-flicks induced by apomorphine. This suggests that limb flicking behaviour may involve interactions with receptors located before the BBB. In contrast, 6-amino-5,6,7,8-tetrahydro-1,2-naphtalenediol HBr (6-ATN), a dopamine-agonist which does not penetrate the BBB, did not induce limb flicks, indicating that receptor stimulation outside the BBB alone is not sufficient to induce limb flicks. We suggest that limb flicks in cats is a behaviour which can be elicited by combined activation of centrally located dopamine receptors and dopamine receptors in the area postrema.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174522
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  • 33
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    Electronic Resource
    Neurokinin A-like immunoreactivity in feline dental pulp: its distribution, origin and coexistence with substance P-like immunoreactivity (1988)
    Springer
    Cell & tissue research 251 (1988), S. 565-569 
    Details
    ISSN: 1432-0878
    Keywords: Neurokinin A ; Substance P ; Dental pulp ; Immunohistochemistry ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution and origin of neurokinin A (NKA)-like immunoreactivity were investigated in feline dental pulp by an indirect immunofluorescence method. NKA-containing nerve fibres with varicosities, which entered the dental pulp via apical foramen, were distributed throughout this tissue. Many NKA-containing nerve fibres were localized around blood vessels, but some were observed apart therefrom. At the odontoblastic layer, thin NKA-containing nerve fibres were observed running straight toward the pulp-predentinal border between odontoblasts. After inferior alveolar nerve section, all NKA-containing nerve fibres disappeared in the dental pulp, while the removal of the superior cervial ganglion resulted in no change in the distribution of these fibres. The correlation of NKA-like immunoreactivity and substance P (SP)-like immunoreactivity was also investigated by double-immunofluorescence technique. The distribution of NKA-containing nerve fibres was very similar to that of SP-containing nerve fibres; it appeared that all NKA-containing nerve fibres contained SP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214004
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  • 34
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    Immunocytochemical analysis of calcitonin gene-related peptide and vasoactive intestinal polypeptide in Merkel cells and cutaneous free nerve endings of cats (1988)
    Springer
    Cell & tissue research 254 (1988), S. 429-437 
    Details
    ISSN: 1432-0878
    Keywords: Calcitonin gene-related peptide (CGRP) ; Vasoactive intestinal polypeptide (VIP) ; Merkel cells ; Free nerve endings ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Calcitonin gene-related peptide (CGRP)-and vasoactive intestinal polypeptide (VIP)-immunoreactivity were observed to coexist in Merkel cells of cats. No differences in peptide content were found between Merkel cells located in epithelia of the hard palate, in hairy and glabrous skin of the upper lip, and in vibrissae follicles. CGRP-and VIP-immunoreactive nerve fibres were also found near CGRP/VIP-immunoreactive Merkel cells. In the vibrissae follicles some CGRP-and VIP-immunoreactive nerve terminals end abutting on the glassy membrane. Other CGRP immunoreactive nerve fibres penetrate the epithelium of the skin and end within it. Electron microscopy of vibrissae follicles revealed that Merkel cell neuntes are not immunostained and that immunostained nerve fibres form unmyelinated bundles before ending freely. Thus, CGRP-and VIP immunoreactive nerve fibres in cat skin do not end as Merkel cell neuntes but as different kinds of free nerve endings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225816
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  • 35
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    Localization of CRF-immunoreactive neurons in the cat medulla oblongata: their presence in the inferior olive (1988)
    Springer
    Cell & tissue research 251 (1988), S. 137-143 
    Details
    ISSN: 1432-0878
    Keywords: Corticotropin-releasing factor (CRF) ; Medulla oblongata ; Inferior olive ; Immunohistochemistry ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Corticotropin releasing factor (CRF)-immunoreactive (IR) perikarya, visualized by the indirect immunoperoxidase method in colchicine-pretreated cats, were localized in many discrete regions of the medulla oblongata. They were found mainly in the dorsal aspect and midline of the medulla oblongata, and more rostrally in the ventrolateral portion. Our results also demonstrated CRF-IR neurons in the rostrocaudal extent of the inferior olive, probably projecting to the cerebellar cortex via thick axons visualized along the lateral edge of the medulla. CRF-IR olivary cells were also found in the pontine cat from which the forebrain was removed, but neither in hypophysectomized nor adrenalectomized cats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215458
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    Neuropeptide distribution in the cervico-thoracic paravertebral ganglia of the cat with particular reference to calcitonin gene-related peptide immunoreactivity (1988)
    Springer
    Cell & tissue research 252 (1988), S. 463-471 
    Details
    ISSN: 1432-0878
    Keywords: Calcitonin gene-related peptide ; Regulatory peptides ; Paravertebral ganglia ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Paraffin sections of cervical and upper thoracic paravertebral ganglia of the cat were investigated by immunohistochemistry using antisera directed against calcitonin gene-related peptide (CGRP). The relationships of CGRP-immunoreactive structures to those exhibiting immunoreactivity to antisera against other regulatory peptides and dopamine-β-hydroxylase (DBH), respectively, were studied in consecutive sections. Singly scattered CGRP-immunoreactive neuronal perikarya were observed in the superior and middle cervical ganglia as well as in the stellate ganglion. These neurons also displayed immunoreactivity to vasoactive intestinal polypeptide (VIP), and some additionally exhibited faint substance-P immunoreactivity. DBH- and neuropeptide Y-immunoreactive ganglion cells were not identical with CGRP-immunoreactive neuronal cell bodies. According to the immunoreactive properties of varicosities, which abut on CGRP/VIP-immunoreactive perikarya, three types of CGRP/VIP-immunoreactive ganglion cells could be distinguished: (1) CGRP/VIP-immunoreactive neurons being surrounded by somatostatin-immunoreactive nerve fibers, (2) neurons being approached by both DBH- and met-enkephalin-immunoreactive varicosities, and (3) neurons receiving both DBH- and neurotensin-immunoreactive fibers. The stellate and upper thoracic ganglia harbored clusters of intensely VIP-immunoreactive somata, which lacked CGRP-immunoreactivity. Fine somatostatin-immunoreactive and coarse CGRP-immunoreactive fibers were distributed within these clusters, whereas patches of neurotensin-immunoreactive fibers were complementarily arranged. At all segmental levels investigated, a few postganglionic neurons were approached by both CGRP-immunoreactive and substance P-immunoreactive varicosities, but lacked a VIP-immunoreactive innervation. Therefore, CGRP/substance P-immunoreactive fiber baskets appeared rather to be of extraganglionic origin than to emerge from intraganglionic CGRP/VIP/SP neurons. CGRP-immunoreactive cell bodies or fibers were absent in clusters of small paraganglionic cells, but some of the solitary paraganglionic cells displayed CGRP-immunoreactivity. Our findings establish the presence of CGRP-immunoreactivity in a population of sympathetic neurons in the cat. A highly differentiated, segment-dependent organizational pattern of neuropeptides in cervico-thoracic paravertebral ganglia was demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214390
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    A re-evaluation of the cytology of cat Pacinian corpuscles (1988)
    Springer
    Cell & tissue research 253 (1988), S. 83-93 
    Details
    ISSN: 1432-0878
    Keywords: Pacinian corpuscle ; Axonal spines ; Inner core lamella ; Inner core cleft ; Elastica ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of cat mesenteric Pacinian corpuscles in cross and longitudinal sections has been examined. The terminal ends of lamellar cells of the inner core have been identified in longitudinal sections through the proximal portion of the inner core. These terminal bulbous expansions contain characteristic concentric membranes of rough endoplasmic reticulum and in some cases masses of oval membranous inclusions. The central axon as seen in cross section is oval in profile, having X-(short) and Y-(long) axes, and each axonal face is characterized by specializations of the axolemma. At the X-axis, the inner lamellae of the inner core tightly abut a smooth axolemma, with no intervening connective tissue matrix, in a manner reminiscent of a neuroepithelium. The axolemma of the Y-axis has numerous axonal spines (microspikes) that project into the cleft in the inner core. The extent of the axolemma having axonal spines can only be appreciated in longitudinal sections. The clefts contain a specialized connective tissue with elastic and collagen fibrils. The connective tissue compartment of fibers and matrix separating individual inner core lamellae is unique, in that it contains extremely thin collagen fibrils measuring approximately 15 nm in diameter. The diameter of collagen fibrils increases as the cleft is approached. Here the fibrils resemble typical endoneural collagen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221743
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    Electronic Resource
    A re-evaluation of the cytology of cat Pacinian corpuscles (1988)
    Springer
    Cell & tissue research 253 (1988), S. 95-103 
    Details
    ISSN: 1432-0878
    Keywords: Pacinian corpuscle ; Axonal spines ; Axonal extreme tip ; Inner core lamella ; Basal lamina-like material ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present report is the second of two studies re-evaluating the cytological characteristics of Pacinian corpuscles. The extreme tip of the axon of a Pacinian corpuscle has been identified and is quite different from the previously described ultraterminal region. The latter is the site where the inner core lamellae begin to terminate and is characterized by a smooth axolemma. The extreme tip lacks inner core lamellae directly abutting the axolemma and is instead characterized by the presence of many axonal spines projecting into a matrix of basal lamina-like material. The extreme tip of the axon thus resembles the organization of the axolemma facing the clefts of the inner core. The axonal spines at the cleft and extreme tip are proposed as a site of restricted current flow due to the tight apposition of inner core lamellae to the axolemma of X-axis. The hemiinner cores thus could restrict current flow to the cleft. These anatomical specializations could represent both a source and a sink for K+ ions during mechano-electric transduction and account in part for the exquisite sensitivity of Pacinian corpuscles to complex pressure waves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221744
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    Electronic Resource
    The influence of middle ear pressure on the otolith system in cats (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 245 (1988), S. 321-324 
    Details
    ISSN: 1434-4726
    Keywords: Otoliths ; Middle ear pressure ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of varying middle ear pressure on the otolith system was investigated in anesthetized cats. Extra-axonal recordings of action potentials were performed in the vestibular nerve fibers and in the neurons in the lateral vestibular nucleus that responded to lateral or anteroposterior steadystate tilt. Positive or negative pressure was applied to the ipsilateral middle ear during the recordings. Seventy-three percent of the fibers and 63% of the neurons responded to changes in the middle ear pressure. These response rates were higher than those previously reported on the units innervating semicircular canals. Findings suggest that the otolith organs are more sensitive to changes in the middle ear pressure than are the semicircular canals. The units responding to lateral tilt were more sensitive to middle ear pressure than those that responded to anteroposterior tilt. Displacement of endolymph caused by pressure changes in the middle ear was considered to have affected the activities of hair cells in otolith organs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464641
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    Erratum (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 585-585 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330614
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  • 41
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    Electronic Resource
    Theoretical studies on conformational preferences of model modified nucleic acid base N6-(N-alanylcarbonyl) adenineNCL Communication No. 4069. (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 37-46 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational preferences of model modified nucleic acid base N6-(N-alanylcarbonyl) adenine, ac6Ade, have been investigated using the quantum chemical PCILO (perturbative configuration interaction using localized orbitals) method. The multidimensional conformational space has been searched using selected grid points formed by combining the various torsion angles that take favored values derived from energy variation with respect to each torsion angle individually.The preferred molecular structure is stabilized by an intramolecular hydrogen bond from N(11)H of the amino acid to N(1) of the adenine. The observed crystal structure conformations for the naturally occurring, anticodon adjacent, threonyl analogs, tc6Ade, correspond to the predicted most stable conformation for the model modified base ac6Ade. Three stable, low energy conformations differing in the orientations of the carboxyl group and the amino acid side chain are predicted within 1 kcal/mol of the most stable structure. The possible bifurcated hydrogen bonding of N(11)H with N(1) and either of the carboxyl oxygens is of minor significance.The indicated orientational flexibility for the carboxyl group and the amino acid side chain may enable convenient probing of the molecular environment, in the vicinity of the anticodon in tRNA, by the amino acid substituent, with only modest changes in energy stabilization.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340106
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    Electronic Resource
    Erratum (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 89-90 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340111
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    A regular periodic table of the elements and its quantum mechanical requirement (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 107-119 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By using the n + (1/2)l filling rule of the atomic Aufbau principle, where n is the principal quantum number and l is the azimuthal quantum number, a new periodic table is presented, its periods having, in order, 8, 18, 18, 32, 42, 50, … elements. The mentioned rule is proposed instead of the n + l rule (or Madelung's rule) which constitutes the quantum mechanical basis of the current periodic table and predicts periods having, in order, 2, 8, 8, 18, 18, 32, 32, 50, … elements. The new periodic table is called “regular” because its groups are formed according to a single rule (namely, the first elements of each period are placed in the same order as the elements of the preceding period), in contrast with the current periodic table, where no simple rule can be applied for the same purpose. The most characteristic feature of the regular periodic table is the fact that its groups are also related in a periodic manner.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340204
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    Control over theoretical descriptions of atoms and molecules. An information theoretic approach to the automatic classification and systematic improvement of approximate wave functions (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 185-190 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A rigorous approach to the study of the quality of theoretical descriptions of atoms and molecules is proposed. Theoretical descriptions, i.e., collections of atomic or molecular properties obtained via quantum chemical methods, are associated with information quantities defined with respect to reference theoretical or experimental data. In this way the comparison of two theoretical descriptions is reduced to the comparison of the respective information quantities. An increase in information is interpreted as improvement of the theoretical description. The aforementioned approach should be useful in problems related to classifications and systematic improvements of approximate wave functions and consequently for comparing the performance of quantum chemical methods in calculations of atomic and molecular properties. This approach should also constitute a powerful tool for the construction of suitable basis sets for use in calculations of atomic and molecular properties.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340209
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  • 45
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    Electronic Resource
    Spin and charge densities from Hiller-Sucher-Feinberg identities. Test calculations for He, B, C, N, O, and F atoms and H2O, N2, and CH3 molecules (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 195-197 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340212
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  • 46
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    Electronic Resource
    Fifth-order constant denominator perturbation therory within a localized bond model: Contributions from single and double excitations (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 497-527 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Fifth-order constant denominator perturbation treatment of all single and double excitations occuring in the third-order perturbation wave function is presented for the perturbation configuration interaction using localized orbitals (PCILO) method. Contributions from triple and quadruple excitations which decay back to singles and doubles at third order are automatically included in this theory. This method is computationally very fast, with an execution speed proportional to N3, Where N is the number of orbitals present. A [2,1] Padé approximate involving only singles and doubles contributions through to fifth order is shown to be remarkably accurate.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330604
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  • 47
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    Electronic Resource
    Hall transformation of exp( - r): Correction of the results (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 563-566 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Owing to an error in his determination of the repulsion integral and the kinetic energy. Hall's results [1] for the ground state of atomic two-electron systems are wrong. Here these results have been corrected. For Z ≤ 5, the results have been obtained by determining the pertinent integrals numerically: but for Z ≥ 5, these can be found sufficiently accurately from Z expansions.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330608
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  • 48
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    Electronic Resource
    Ab-initio calculation of resonance states of H2O (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 567-576 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a dissociation attachment experiment of water, three peaks were observed at 7,9, and 12 eV. The origin of the third peak has been believed to be 2B2. However, the calculated energy of this state is 0.6 eV higher than the experimental value. This discrepancy is quite large compared with the case of the lower two peaks. In this study we propose new candidates for resonant states responsible for the third peak. The configurations considered are (3a1)-1(3pa1)2, (3a1)-1(3pb1)2, (3a1)-1(3pb2)2, (3a1)-1(3pa1)1(3pb1)1, (3a1)-1(3pb2)1(3pa1)1, and (3a1)-1(3pb2)1(3pb1)1 which have the parent state (3a1)-1(3pa1)1, (3a1)-1(3pb1)1, or (3a1)-1(3pb2)1. The energy levels arising from these configurations are calculated by a method of configuration interaction. A Few resonance states, which could be responsible for the third peak, are found. New decay process of these states are proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330609
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    The sequential product of geminals and the ground states of some atoms (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 9-14 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By means of the SPG function which is associated with an extreme point of the set of N-representable second-order reduced density matrices, an attempt is made to perform the calculations of the ground states of some atoms with four electrons such as Be. The results show that the SPG function is as suitable as the well-known AGP function for approximating the ground states of atoms and molecules.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340103
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  • 50
    Electronic Resource
    Electronic Resource
    A sequential product of geminals and its applications (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 15-23 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper, an SPG function, which is associated with an extreme point of the set of N-representable second-order reduced density matrices, is used to perform the calculation of the ground state energy of LiH with the variation of internuclear separation. The result of our calculation essentially is in accordance with that of AGP function.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340104
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    The concept of the topological atom within the MO-LCAO approach. II. On the nature of the nephelauxetic effect (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 1-8 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new MO-LCAO description of the nephelauxetic effect is proposed based on the concept of the topological atom and on the method of reduced density matrices. This approach allows one to overcome some conceptual difficulties of ligand-field theory and to derive effective parameters of d-d electron repulsion of a bound transition-metal in a proper way. The two ligand-field mechanisms of the nephelauxetic effect - the central field covalency and the symmetry-restricted covalency - are clarified and generalized. In addition, a new factor, important for the nephelauxetic effect is found: its size-dependence on the region of the topological atom.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340102
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    A Crystal Orbital approach for two- and three-dimensional solids on the basis of CNDO/INDO Hamiltonians. Basis equations (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 47-71 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Hartree-Fock (HF) self-consistent field (SCF) crystal orbital (CO) formalism for two- and three-dimensional (2D/3D) solids on the basis of semiempirical CNDO/INDO (complete neglect of differential overlap; intermediate neglect of differential overlap) Hamiltonians is presented. The employed SCF variants allow for the treatment of atomic species up to bromine under the inclusion of the first (i.e., 3d) transition metal series. Band structure investigations of 2D and 3D materials containing more than 30 atoms per unit cell are feasible by the present SCF HF CO formalism. The theoretical background of the computational scheme is given in this contribution. Special emphasis is placed on physically reliable truncation criteria for the lattice sums, the adaptation of the crystal symmetry in k space, as well as the suitable choice of domains in Brillouin zone (BZ) integrations required in the determination of charge-density matrices. The capability and limitations of the semiempirical SCF HF CO approach is demonstrated for some simpler solids by comparing the present computational results with those of ab initio CO schemes as well as conventional numerical methods in soid-state theory. The employed model solids are graphite and BN (2D and 3D networks for both solids) as well as diamond, silicon, germanium, and TiS2.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340107
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    Long distance electron transfer (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 1-22 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantum mechanical models to treat long distance electron transfer are being developed. The model is based on the theory of R.A. Marcus. Our contribution is in the calculation of the electron coupling factor k. Estimations of the latter number, as well as the bond and solvent relaxation energies, λi and λo, respectively, are necessary to be able to calculate the rate constant for a reaction of the conductivity in an electric field. k may be approximately calculated from orbital energy differences at avoided crossings between orbitals localized in different parts of the system. A novel spectroscopic NDO method is suggested in which one may include any atom of the periodic table. Another problem discussed is the inclusion of electronic relaxation effects of the solvent or protein in the calculation. Applications are made to systems where metal ions are connected by organic bridges of different kinds such as dipyridine with coplanar and perpendicular pyridyl groups. As expected the electronic factor depends strongly on the conformation of the bridge. A strong conformational dependence is also obtained for a saturated bridge of the type NH2 · (CH2)n · NH2. In another study we use an α helix as a bridge between two metal ions. If one glycine in this α-helix is substituted by phenylalanine the electronic factor increases by factors of 1.5-10. It is suggested, however, that larger enhancement factors are possible if an aromatic group is positioned in a favorable way. The CNDO/S method is used to study the charge separation process in a bichromophoric molecule and in the reaction center (RC) of Rhodopseudomonas viridis. In those cases where the electronic coupling is large enough for the charge transfer states to be seen in the spectrum, the calculated results agree well with the experimental ones, but suggest a novel assignment. The CNDO/S results verify that electron transfer is possible through saturated spacers. In the special pair of RC the S1 state is calculated at approximately the correct position. Like the ground state, it has a delocalized character.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340704
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  • 54
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    Electrostatic interactions and conformation of some thromboxane antagonists (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 67-84 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A class of thromboxane antagonists exists where the prostaglandin side chain containing the C16 hydroxyl moiety is replaced by a phenyl ring, and the bridged six-membered pyranose moiety by cyclohexane, pyranose and dioxane ring systems. Analysis of antagonist potency data in terms of a binding constant model previously used for membrane bound receptor-drug interactions shows that the major patterns of antagonist potency are governed as much by axial/equatorial conformer preference of the phenyl moiety and its orientation as by electrostatic effects of the aliphatic ring oxygen atoms. The conformational restriction of the two substituted side chains of the σ-bonded 6-membered ring is shown to be a primary requirement for binding to thromboxane receptors, and a quantitative separation of electrostatic and conformational components in the potency data is attempted.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340708
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    An ab initio molecular orbital study of hydrogen bonding and ion-molecule association in model systems for DNA bases (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 119-135 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio calculations have been performed to investigate hydrogen bonding and ion-molecule association in complexes of H2O with the neutral, protonated, and Li+ complexes of N-formylformaldehyde and N-formylformamidine. In the complexes with the neutral bases, H2O assumes an in-plane bridging position in the amide and amidine regions. The most stable complex is the bridging N-formylformamidine-H2O complex in the amidine region, which has an MP2/6-31 + G(d,p) binding energy of -9 kcal/mol. Hydrogen bonded complexes of H2O with the oxygen-protonated bases have open structures with the protonated bases as proton donors, and binding energies ranging from -16 to -24 kcal/mol. Nitrogen protonation of N-formylformamidine leads to an equilibrium chelated hydrogen bonded structure with a stabilization energy of -21 kcal/mol. When Li+ associates with these bases at a carbonyl oxygen, hydrogen-bonded bridging structures with H2O reappear, and wobble complexes exist in the amide and amidine regions of N-formylformaldehyde and N-formylformamidine. These complexes have binding energies of -13 to -14 kcal/mol. However, the most stable comples has H2O directly bonded to Li+, with an MP2 binding energy of -30 kcal/mol. No hydrogen bonded structures of H2O with N-formylformamidine exist in the amide region when Li+ associates with this base at the C=N group. Hydrogen bond energies computed at the single-determinant Hartree-Fock level with the 6-31G(d) basis set approximate correlated MP2/6-31 + G(d, p) energies to within 1 kcal/mol for all of the neutral and charged complexes. However, when H2O is bonded to Li+, HF6-31G(d) association energies overestimate MP2/6-31 + G(d, p) energies by 3 kcal/mol.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340712
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    Electronic Resource
    Dependence of MO shapes on a continuous measure of delocalization (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 1-13 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Whereas localization of orbitals has long been a tool for a semiclassical interpretation of chemical properties, it is in fact electron delocalization that is a fundamental property of quantum mechanical molecules. A mathematically well-defined measure is suggested for the degree of delocalization of molecular orbitals. It is shown that an orbital set of maximum delocalization exists for which the degree of delocalization depends on the charge distribution of the molecule. Hartree-Fock canonical orbitals are definitely more localized than the most uniformaly distributed MO's giving an equivalent description of the molecule. The changes in the geometrical shape of molecular orbitals are studied passing (quasi-) continuously from the strongly localized description towards the most delocalized picture. In the case of charge-inhomogeneities even the most delocalized orbitals remain rather compact. The degree of maximum delocalization may be correlated with chemical properties such as reactivity. The shape distortion of MO's under the perturbing effect of other ions and small molecules is investigated in several examples.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340804
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    Electronic Resource
    Density and density matrix from optimized linearly independent product basis functions for Be (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 43-49 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The density matrix was computed from the density using basis orbitals which form linearly independent products (LIP). Calculations were performed on the Be atom using LIP bases containing several of the natural spin orbitals from an accurate nonrelativistic 650-term configuration interaction (CI) wavefunction. Calculations were also performed using a basis set of 6 s-type orbitals optimized so that the lowest eigenvalue, d1, of the overlap matrix of products is maximized and the energy of a small CI wavefunction is minimized. The value of d1 in the optimized basis is 1 × 10-7. The density and the potential energy obtained from the 650-term CI wavefunction were accurately reproduced by the density matrix expressed in the optimized LIP basis, but the kinetic energy was somewhat less accurate.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340809
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    Electronic Resource
    Geometry optimization using local-density functional methods: Numerical aspects (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 77-84 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The need to perform a numerical integration of the exchange-correlation functional because of its non-analyticity severely complicates the accurate application of local-density functional methods to molecules and clusters. The optimal choice of grid points for this integration and the estimation of the error made by the choice are subtle considerations. In particular, because the position and/or weighting of each grid point must change when the nuclear positions change, these errors are most noticeable when different geometries are compared. We have determined a method of grid point selection and weighting that reduces these errors. We have also determined a simple method of estimating the extent of the error made in the particular density of points used for the grid. These results are illustrated for a selection of small molecules.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340813
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    Topological electronic rules for polycyclic hydrocarbons - quantum chemical deductions directly from structural formulas (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 143-147 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: All bicyclo[p.q.0] conjugated hydrocarbons are found to fall into ten homolog classes each characterized by the numbers of nonbonding, bonding, and antibonding molecular-orbitals of its first prototype and by the prototype itself. The energy level patterns are obtained by the new “structural covariance” pictorial rules directly from structural formulas. The HOMO-LUMO types, aromaticity or three types of nonaromatic behavior, and reactivities towards nucleophiles or electrophiles thereby also result.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340818
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    Electronic Resource
    Calculation of harmonic frequencies and harmonic force fields by the hartree-fock-slater method (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 173-181 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Results are presented from Hartree-Fock-Slater (HFS) calculations on harmonic frequencies and force constants of H2O, H2S, NH3, PH3, CH4, SiH4, and C2H4. Both frequencies and force constants were calculated by a numerical (finite difference) differentiation of analytical energy gradients. It is shown by a comparison with experimental data and results from ab initio Hartree-Fock (HF) calculations that the HFS-method provides harmonic frequencies and force constants in at least as good agreement with experiment as the HF-scheme.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340821
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    A progress report on the status of the COLUMBUS MRCI program system (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 149-165 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The COLUMBUS program system is a collection of Fortran programs for performing general multireference single- and double-excitation configuration interaction (MRSDCI) wave function optimization based on the graphical unitary group approach. The program system also includes integral generation, SCF and MCSCF orbital optimization, integral transformation, and wave function analysis programs. The original program system was written in 1980 to 1981. Since that time, it has evolved into one of the most popular MRSDCI program systems used in the computational chemistry community. The discussion of this evolution will include the exploitation of efficient matrix-matrix and matrix-vector product computational kernels, the use of generally contracted symmetry-adapted orbital basis sets, general Hamiltonian diagonalization procedures, energy-based internal walk selection, flexible DRT specification, improved coupling-coefficient evaluation methods, coupled-pair functional and multireference CPF capabilities, and density matrix construction. The numerous versions of the program system that are maintained at different sites and on different computers are now in the process of being merged. The source code for this combined version will be made available to the computational chemistry community. The source code for a specific computer may be generated from the source code for another computer by a single pass through a simple filter utility that is included with the program system. The directly supported computers will initially include various models of VAX, Cray, FPS, IBM, CDC, and ETA machines with the addition of other machines shortly thereafter. The ongoing developments of the COLUMBUS system that are discussed include a new method for computing analytic energy gradients for MRSDCI wave functions. This effective-density-matrix based method avoids the “coupled perturbed MCSCF” solutions for each coordinate direction, avoids the transformation of any derivative-integral quantities from the AO to the MO basis, avoids the transformation of the coupling coefficients from the MO to the AO basis, allows a subset of the MCSCF doubly occupied orbitals to be frozen in the CI wave function, and allows the MRSDCI wave function to be generated from general reference CSFs that are not necessarily related to the MCSCF expansion CSFs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340819
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    Electronic Resource
    Theoretical study of the geometry of Mn5 (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 231-236 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The geometry of Mn5 in rare gas matrices has been proposed to be a planar pentagon with 25 unpaired electrons. Simple unrestricted Hartree-Fock (UHF) calculations have been carried out using a basis of STO-6G for 1s, 2s, and 2p orbitals with STO-4G for 3s, 3p, 3d, 4s, and 4p in the HONDO5 program. The structure is optimized at the UHF level using the analytic gradient formalism for a planar pentagon. Binding energies and spinmixing are given for the optimized structure.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340827
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    Electronic Resource
    Molecular hardness and softness parameters and their use in chemistry (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 349-366 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The semiempirical Atoms-in-a-Molecule (AIM) hardness matrix, η, is defined, using the usual finite difference formula, ηii = Ii - Ai, for the diagonal AIM hardness and the Ohno formula, ηij = 1/(a2 + R2ij)1/2, for the off-diagonal AIM hardness. The Ohno formula is shown to exhibit the correct asymptotic behavior and satisfies the relevant stability criterion. The normal displacements in the AIM electron populations are examined for pyrrole and N-methyl pyrrole, and their relation to the polarization channels is briefly discussed. The new AIM hardness matrix is also tested by comparing the predicted global hardnesses with the corresponding experimental finite difference data for selected diatomics and triatomics. Finally implications of the hardness combination rules are examined and the corresponding softness combination rules are used to calculate the regional and global softnesses of selected molecules. We examine how the regional softnesses reflect known trends in selectivity of protonation of five membered heterocycles, and comment on the signs of the AIM fukui function and the Hard-Soft-Acids-and-Bases principle.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340840
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    Electronic Resource
    Modified breit-pauli hamiltonian suitable for variational calculations (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 425-430 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Breit-Pauli type Hamiltonian with an effective positive term in substitution of the Darwin term is proposed for variational calculations. The Hamiltonian is bounded from below and does not exhibit variational collapse. Calculations on one electron atoms for the ground state, 2pl/2 and 2p3/2 states are presented. The results essentially coincide with those obtained from first order perturbation theory.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340845
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    Electronic Resource
    Titanium in large silicon clusters (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 297-308 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of molecular ab initio methods to investigate the electronic structure of localized impurities in semiconductors requires the study of the convergence of the results with increasing cluster size. Here we compare results for interstitial Ti in silicon, obtained with clusters of increasing size: TiSi10H16, TiSi30H40, and TiSi66H64. These clusters contain one, two, or three shells of silicon atoms, respectively, centered around Ti at a Td interstitial site. The hydrogen atoms serve as saturators of the dangling bonds. The Si core electrons are replaced by an effective potential. The calculations are based on open shell RHF theory and limited CI extensions. The charge distribution in the central part of the three clusters is very similar. In the clusters the partially occupied orbitals are much more delocalized than the 3d orbitals in the free ions. The total impurity-induced electronic charge, however, is quite localized, due to the compensating response of the Si closed shell density. Ionization of the impurity also causes a compensating response of the Si closed shells: only about 10% of the density difference is in the impurity region and the major part is behind the outermost shell of Si atoms. Transition metal associated (3d-like) excitation energies are not very dependent on the cluster size, and the relative ordering of the lowest lying states remains unchanged. Impurity associated ionization energies decrease considerably due to the extra relaxation offered by the additional shells of Si atoms. Our results indicate that a reliable description of interstitial transition metals in silicon can be provided by calculations on reasonably small clusters: Si30H40 is sufficiently large.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340834
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    Theoretical kinetic and thermodynamic study on the disilene-silylsilylene isomerization (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 343-347 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The titled isomerization has been studied at the HF/3-21G level. The changes in thermodynamic functions, equilibrium constant K(T), conversion efficiency C(T), and the rate constant k(T) for the isomerization have been calculated using our energies of the reactant (R), transition state (TS), and product (P), their harmonic vibrational frequencies, and the classical and corrected barrier (by vibrational zero-point energies). In the range of temperature, 300-1200K, ΔH 〈 0, ΔS 〉 0 and ΔG 〈 0; i.e., it is exothermic, increasing in the entropy, and spontaneous reaction. ΔS≠ 〈 0, log A is about 12.0 ±0.15 (s-1), but the k(T) is from 2.627 × 10(-33) to 6.933 × 10(8) (5-1); i.e., it passes through a tight TS, the A factor changes little, but the rate constant varies rapidly with the temperature. These results agree with the fact that the isomerization occurs readily at high temperature. Furthermore, Newman's mechanism, 2SiH2 → (H2SiSiH2)* → (HSiSiH3)* → Si2H2 + H2, is supported. Similarly, the isomerization, HDSiSiH2 → HSiSiDH2, is also studied.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340839
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    Electronic Resource
    Iteration of the many-particle schrödinger equation in momentum space (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 437-444 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A generalization of the Fourier convolution theorem is used to iterate the many-particle Schrödinger equation in momentum space. The method is applied using hyperspherical coordinates, with many-dimensional hydrogenlike wave functions as the starting point for iteration. The problem of angular integration is converted into a problem of differentiation by means of the theory of harmonic polynomials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340847
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    Relativistic CASSCF/CI calculations: Applications to transition metal dihydrides (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 465-476 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A complete active space MCSCF (multi-configuration self-consistent field) scheme (CASSCF) using relativistic effective potentials followed by configuration interaction and relativistic CI calculations provides a very good description of the electronic states and potential energy surfaces of transition metal dihydrides. Such calculations are of considerable value not only in our understanding of the transition metal-hydrogen bonding but also in the prediction of the barrier to insert the metal atom into the H2 bond. All-electron CASSCF/CI calculations are carried out on twelve electronic states of CoH2. Comparable RECP-CASSCF/CI calculations are also carried out to show that the RECP-CASSCF/CI calculations provide an accurate method for the investigation of transition metal compounds. The general method of RECP-CASSCF/CI calculations for molecules containing heavy atoms is described. The calculations on CoH2 are compared with similar calculations on ScH2, YH2, PtH2, and PdH2. A critical comparison of all these transition metal hydrides reveals that in general the low-spin excited metal atom inserts into H2 spontaneously while the high spin ground state atom has to surmount a large barrier.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340850
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    Electronic Resource
    The nonabelian two-dimensional algebra and the franck-condon integral (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 503-505 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two mapping operators are used to relate the eigenstates of two distorted and displaced oscillators. It is found that these operators satisfy a nonabelian two-dimensional algebra. We exemplify the method by calculating the Franck-Condon integral for the case of two harmonic oscillator wells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340855
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    Electronic Resource
    Use of quantum mechanical models in studies of reaction mechanisms (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 557-566 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problems involved in determining the mechanisms of reactions by quantum mechanical calculations are discussed. Various precautions must be taken if the results of any calculation are to be chemically meaningful. Ab initio studies of reactions must also be carried out at a high level, using large basis sets and allowing for electron correlation. Such calculations are usually restricted to the simplest example of a reaction, which is often untypical. More information can usually be obtained at far less cost through AM1 calculations for a number of examples of a reaction for which experimental data are available. These points are illustrated by recent studies of the Cope rearrangement.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340860
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    Symbolic computation in quantum mechanics. Several simple examples (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 537-548 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aim of this article is to illustrate the use of symbolic computation in solving some problems in quantum theory. Emphasis will be given to the possibility of manipulating expressions symbolically and to the interface of numerical and algebraic languages. The illustrate the use of the scientific computation language Maple as a research tool, we present our work on lower energy bounds for anharmonic oscillators and on the spherical Zeeman effect. Another example consists in the perturbation calculations of the N-dimensional hydrogen atom, keeping the quantum labels in general form. Further, we describe the interface of Maple, Fortran, and the typesetting language, Troff. The basic feature is illustrated on the application of the inner projection technique and of the method of intermediate Hamiltonians on the benzene molecule as well as on the geminal approach to the butadiene molecule; the main calculations were first done in Maple and then transferred into Fortran's notation so that Fortran subroutines could be used. Finally, the results either in Maple or in Fortran can be transferred to a Troff file.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340858
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    Simple models for describing the fragmentation behavior of multiply charged cations (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 567-573 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potential energy curve describing the fragmentation of a diatomic dication AB2+ is considered as arising from an avoided crossing between an attractive diabatic curve (correlating with A2+ + B) and a repulsive diabatic curve (correlating with A+ + B+). The simplest avoided-crossing (AC) model neglects diabatic coupling and polarization and leads to useful predictions of the transition structure bond length (rTS) and the kinetic energy released (T) in fragmentations of dicationic systems in which the difference (Δ1) between the ionization energies of A+ and B is small. When Δ1 is not small, it is necessary to include diabatic coupling and polarization in the treatment. The resultant ACDCP (avoided crossing with diabatic coupling and polarization) model provides very satisfactory estimates of rTS and T for both small and large Δ1. Its implementation requires only atomic ionization energy and polarizability data and comes at virtually no computational cost. Both the AC and ACDCP models are readily generalized to fragmentations of more highly charged cations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340861
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    Spatial correlation of electrons in metals (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 655-664 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of electron-electron repulsions is assessed, primarily in the expanded fluid alkali metals, by confronting experimental data on these systems with the predictions of theory. This is usefully divided into two types of approach: (i)full inclusion of the long-range Coulomb interaction e2/rij between electrons i and j, but perturbative treatment of electron-ion interaction and(ii)the simplified on-site interaction described by the Hubbard U.The main conclusion is that both electron-ion and electron-electron correlations are of major importance in the expanded fluid alkali metals, and especially in Cs. The momentum distribution of the conduction electrons is changed in a very important quantitative way from the predictions of the jellium model at the same density by the electron-ion interaction. This leads to a metal-insulator transition at a much higher electron density than the jellium prediction. The relevance of this conclusion to crystalline alkalis is finally referred to.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340867
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    Electrostatic potential maps of flavone acetic acids: A new class of antitumor drugs (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 697-705 
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    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complete geometry optimizations have been carried out with the AM1 method on flavone acetic acid and several of its derivatives. Molecular electrostatic potential maps have been used to predict new com.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340870
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    Erratum (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 741-741 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340876
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    Masthead (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340101
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    Electronic Resource
    A spin-free form of valence bond theory (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 25-36 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Classical valence bond theory is recast in a spin-free form which provides a practicable route to ab initio calculations of molecular electronic structure. The approach is simple and direct and requires only efficient algorithms for the generation and processing of permutations and the handling of Rumer diagrams: it makes modest demands on computing power and pilot calculations have indeed been performed entirely within the fast memory of a personal computer, which should be sufficient for dealing with systems possessing up to 10 electrons outside a closed shell. Simple applications confirm the conclusion of Cooper et al. [1] that, by using strongly overlapping orbitals, a small number of classical (nonpolar) structures can give results close to those obtained in a “full CI” calculation.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340105
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  • 78
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    Electronic Resource
    The role of hydrophobicity in the Ames test. The correlation of the mutagenicity of nitropolycyclic hydrocarbons with partition coefficients and molecular orbital indices (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 91-101 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A set of 20 nitropolycyclic aromatic hydrocarbons, whose mutagenicity has been determined in the Ames test, has been studied using octanol-water partition coefficients (P) as a measure of relative hydrophobicity and molecular orbital energies to account for variation in their electronic characteristics. A good structure-activity relationship was found using log P and ∊LUMO. The latter were taken from the results of ab initio calculations performed by Maynard, Pedersen, Posner, and McKinney [7] and were also calculated by the MNDO method. The dependence of mutagenicity on hydrophobicity was found to be similar to that observed for triazenes [2]. ∊LUMO values calculated by MNDO and STO-3G were found to be strongly correlated, and the role of hydrophobicity in correlating mutagenicity was not significantly affected by the molecular orbital model employed.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340202
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  • 79
    Electronic Resource
    Electronic Resource
    Molecular conformations and molecular shape: A discrete characterization of continua of van der Waals surfaces (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 517-526 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A characterization of molecular model surfaces is proposed. It is based on a graph associated with the van der Waals surface, defined by the detailed information on the interpenetration of van der Waals spheres of the constituent atoms. This “van der Waals graph” describes the three-dimensional body of the molecule, and it does not coincide in general with the less informative bond graph obtainable from the molecular skeleton.The description in terms of the graph reveals clearly the changes in molecular shape induced by conformational rearrangements. The nuclear configurations can be classified by the graph associated with the molecular surface, and the graph-theoretical analysis provides a rigorous partitioning of the configurational space based on shape properties.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340605
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  • 80
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    Electronic Resource
    The use of symmetry in reciprocal space integrations. Asymmetric units and weighting factors for numerical integration procedures in any crystal symmetry (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 571-594 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A systematic collection of spatial domains for reciprocal space integrations is derived for all possible crystal symmetries. This set can be used as a simpler alternative to the conventional Brillouin zones. The analysis is restricted to integrations where the function in the integrand satisfies inversion symmetry in k space. In this case only 24 different spatial domains have to be defined in order to allow for k space integrations in the 230 different crystal symmetries. A graphic representation of the asymmetric unit for each of the 24 integration domains is given. Special positions and the associated weighting factors required for numerical integrations in theoretical solid-state approaches are tabulated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340609
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  • 81
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    Electronic Resource
    Thermodynamic calculations on biological molecules (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 221-234 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Application of free-energy simulation methods to the calculation of thermodynamic properties for biologically relevant processes will be presented. Attention will be given to the usefulness of thermodynamic methods to explore the accuracy of empirical energy functions. Calculations of aqueous hydration and binding thermodynamics for drug molecules (trimethoprim and other related compounds) to biological targets (the enzyme dihydrofolate reductase) will be presented. In these applications we will discuss differences in “binding modes” for different drugs and the ability of thermodynamic methods to predict these changes. Finally, comments will be made regarding the free energy derivative methods and coordinate-coupled free energy calculations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340720
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  • 82
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    Electronic Resource
    A rational selection of graph-theoretical indices in the QSAR (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 267-285 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper we have addressed an important problem: how to develop a strategy for identification of the topological indices which are most important in establishing a model for structure-activity analysis. In particular we consider a rational selection of graph theoretical (topological) indices in QSAR. The approach is illustrated by the study of the toxicity of ethers on mice. The indices examined include the connectivity indices based on adjacency matrix, the conceptually related graph distance indices, and an information theoretic index based on partitioning of electrons in various domains. We have outlined the similarities and differences and discuss advantages and limitations among different approaches. Our emphasis is on the problem how to select in a rational way appropriate graph-theoretical descriptors and how to introduce higher “corrections” in order to improve derived correlation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340724
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  • 83
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    Electronic Resource
    Vibrational frequencies and assignments for some isotopomers of urcail using a scaled ab initio force field (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 1-17 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vibrational frequencies and IR band intensities for 18 isotopomers of uracil, including deuterated 15N and 18O species, have been calculated using the scaled ab initio force field of Ref. 1. The results obtained are compared with available experimental data, and a number of refinements in former assignments are proposed. The good agreement between the calculated and experimental frequencies confirms the reliability of the scaled quantum mechanical-force field.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330102
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  • 84
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    Electronic Resource
    The complexes of phenyl acetylene with HF, H2O, and NH3: An ab initio study (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 69-76 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenyl acetylene complexes with HF, H2O, and NH3 are investigated with ab initio molecular orbital calculations using the 6-31G Gaussian basis set. HF is found to form a π complex, whereas H2O and NH3 form σ complexes. Observations of experimental spectroscopic shifts are rationalized.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330202
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  • 85
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    Electronic Resource
    Announcement (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 169-169 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330208
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  • 86
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    Electronic Resource
    Masthead (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330301
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  • 87
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    Electronic Resource
    Masthead (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330401
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  • 88
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    Electronic Resource
    Self-consistent reaction field calculations on the proton transfer in ammonia-formic acid systems as a model for hydrogen bonding in amino acids in solution (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 41-52 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction field (RF) model of solvent effects, implemented within the SCF-CNDO/2 scheme of calculation, has been applied to analyze the proton transfer in the NH3…HCOOH system in the presence of several polarizable media. The aim of such a study was to characterize the tatutomeric equilibrium between the neutral and zwiterionic forms of H-bonded amino acids in aprotic solvents. Qualitative results concerning the energetics of this equilbrium show the stabilization of two different H-bonded complexes, corresponding to two separate minima in the free energy surface. These well known double minima potentials are found to be dependent on both the intermolecular N—O distance and the strength of the reaction field. The behavior of this model is qualitatively consistent with experimental observations of nitrogen-substituted amino acids in solution: both show, for low values of the dielectric constant, tautomeric equilibria where the H-bonded complexes appear to be more stable than the corresponding monomeric forms. The charge transfer process associated with the proton migration along the H-bond is also discussed. It is found that the amount of charge transferred increases with the N—O distance and with the RF strength, In order to test the general approach and compare it with previous work, calculations on the real monomeric systems glycine, β-alanine, and γ-amino butyric acid was also performed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330105
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  • 89
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    Electronic Resource
    Analytical potential from ab initio calculations for the Fe+-H2O and Feo-H2O systems (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 77-85 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analytical intermolecular potentials for the Fe+-H2O and Feo-H2O systems have been determined from ab initio calculations. Interaction energies for a lot of points along the two potential energy surfaces were calculated using Huzinga's MINI-2 basis set. The results obtained were fitted to an analytical function containing 11 adjustable parameters that we have already used with success for the Fe2+-H2O system. The goodness of the generated intermolecular potentials is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330203
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  • 90
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    Electronic Resource
    Inclusion of relativistic effects into ZDO methods. II. Solavation of metal complexes (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 159-167 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The quasirelativistic CNDO/1 method has been in investigating the geometry, electronic structure, and redox stability of metal complexes. The systems of [Co(NH3)6]q and [MCl4]q, M being Ni, Pd, and Pt, have been studied. A modified Germer model of solvation has been implemented into the method. This yields reliable results on the redox stability of complexes in aqueous solutions. The calculated excitation energies resemble the electronic spectra of [MCl4]2- complexes.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330207
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  • 91
    Electronic Resource
    Electronic Resource
    The energy of the homogeneous electron gas to second order (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 173-175 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The energy of an infinite, homogeneous electron gas is examined by second order perturbation theory using a Hartee-Fock rather than a noninteracting particle unperturbed state. The second order energy still diverges for small promotions k, albert than as ln|ln k| rather than as In k.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330302
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  • 92
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    Electronic Resource
    Quantum phenomena in small semiconductor structures and devicesInvited lectures presented at the Kandy Symposium on Condensed Matter Physics, Kandy, Sri Lanka, April 20-25, 1987. (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 217-245 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ability to artificially structure new semiconductor materials on an atomic scale, using advanced crystal growth methods such as molecular beam epitaxy and metal organic chemical vapor deposition, has led recently to the observation of new physical phenomena as well as the creation of entirely new classes of devices based on band gap and wave function engineering. In these lectures an elementary introduction is given to the quantum aspects of these new structures.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330306
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  • 93
    Electronic Resource
    Electronic Resource
    Variational energy derivatives and perturbation theory (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 271-277 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this note we discuss the variational forms of the energy derivatives and the method of obtaining them. We show that perturbation theory can be formulated in terms of stationary energy derivatives and that this formulation extends the idea of the Hylleraas functional to infinite order and excited states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330403
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  • 94
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    Electronic Resource
    Dimensionality dependence of total energy of closed shells in a bare Coulomb field for large atomic number (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 301-304 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For Z particles moving independently in an unscreened Coulomb potential energy -Ze2/r, it is known that the total energy E = -(3/2)1/3Z7/3 in nonrelativistic theory as Z→∞. The generalization of this result to d dimensions in the same asymptotice limit is obtained as \documentclass{article}\pagestyle{empty}\begin{document}$$E(Z,d) = - \frac{{2\left({\frac{{d!}}{4}} \right)^{1 - (2/d)} }}{{(d - 1)!(d - 2)}}Z^{3 - (2/d)},$$\end{document} which includes the known result above for the three-dimensional case.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330405
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  • 95
    Electronic Resource
    Electronic Resource
    Announcement (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 369-369 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330410
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  • 96
    Electronic Resource
    Electronic Resource
    Masthead (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330501
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  • 97
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    An examination of perturbation-variational theory and scaling at fifth order (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 373-394 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We examine various perturbation-variational approximations for molecular electronic energy when the fifth-order perturbational energies are available. Such theories require very little additional computation once the sequence of perturbation energies are known yet supply a bound even when the peturbation sequence is poorly convergent. We choose for computational examples results obtained very rapidly from a zeroth order wave function consisting of doubly occupied localized bonds and examine polarization within these bonds, delocalization, and bond breaking. In general, we find that the fifth-order energy itself, and especially the [2, 1] Padé approximant on this sequence, are especially accurate in estimating the total energy and more accurate than any variational scheme when the zeroth order localized wave function is a good description of the electronic structure. The variational results, however, are nearly as accurate, and a [1, 0] Padé on the sequence of variational results is remarkably robust, even in those cases where the perturbation sequence is poorly defined.We also examine several scaling techniques, or partitionings of the Hamiltonian. Although these scaling techniques do accelerate convergence of the perturbation sequence, none that we examine give better results, than the [2, 1] padé, which is independent of any scaling.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330502
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  • 98
    Electronic Resource
    Electronic Resource
    Masthead (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988) 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330601
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  • 99
    Electronic Resource
    Electronic Resource
    Extrapolation of the total energy of polymers to the bulk limit using generalized padé approximants (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 225-229 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Generalized Padé approximants are used to extrapolate the total energy of polymers described by alternant Hamiltonians to the bulk limit. The method provides an upper bound to the energy. The origin of (quasi) periodic oscillations of the energy per unit cell as the function of the number of unit cells is enlightened through analysis of the moments of the Hamiltonian.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340305
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  • 100
    Electronic Resource
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    Intershell nl4f electron correlation effects (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 279-288 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pair correlation energies for some nl4f pairs of the ground state of the Yb atom are calculated for the first time. The partial wave (PW) increments to the second-order pair energies are generated using numerical first-order radial pair functions obtained as the solution of two-dimensional differential equations. The analysis of the PWs contributions shows the dominant role of the df, fg, and gh PWs for the 4d4f pair, of the pf and dg PWs for the 4p4f and 5p4f pairs, and of the sf and pg PWs for the 4s4f, 5s4f, and 6s4f pairs. A discussion of the similarities and differences of the structure of the correlation energy found in this paper with those calculated earlier for smaller atoms is given.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340309
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